A Heart of Stone
by Tyranno's girl
Summary: Sometimes having a heart of stone is a blessing. Naruto Uzumaki found himself wishing that at times, especially being surrounded by strange beings who have no idea how human emotion works. All they know is that his father sacrificed himself so that he may live... And now Naruto has to take up his reigns as a leader. Steven Universe AU, eventual pairings inside.
1. Prologue

**A/N: So, I have no idea where I'm going with this. I just needed to write _something_ vague and unrelated to my original writing work and since 'crossovers-but-not-really' fics have always been good at relaxing me, I decided to do this one. **

**Not even beating around the bush, this one is inspired by the show that has taken the internet by storm _Steven Universe_. Personally for me, the show is... alright. Not my favorite but I do highly congratulate Rebecca Sugar on what she has managed to do. **

**This fic is going to have some elements from the show but, otherwise, I'm taking my own liberties with the alien cultures and such.**

 **Warnings for: Future SaiNaruSasu, one-sided FugaMina, Minato/Kushina, SasoDei, and, of course, KisaIta.**

* * *

He had been warm.

Then cold.

The coldness had seeped in far faster than he had been expecting. It pricked and stung at his sensitive skin, making him far... too... uncomfortable.

He needed it to stop.

It wasn't just the cold, it was the... the air around his tiny frame. There was... negativity. There was... pain.

Sadness.

Sadness was seeping into him. The feeling overwhelmed him and, in conjunction with the cold, all he could do was let out the vocal summation of his feelings.

But even as his pitiful wails left his lips, the negativity around him increased moreso.

"Don't you tell me to 'calm down'! Look at where we are now! All thanks to this _miserable_ human brat!"

"Shut the hell up, Fugaku... Please. After everything I've..." The second voice, a woman on the brink of exhaustion, coughed out, "Been through today. Shut. Up."

Fugaku and the woman kept their exchange of harsh words going, all while the small bundle in the room still sniffled and wailed. Why were they being so cruel to one another? Why was no one helping him?

Sparkling blue eyes opened up from the squirming bundle, trying to take in their surroundings. They saw an older man with graying black hair tied into a low pony-tail. He was dressed in black robes that followed every sharp gesture he made towards the visibly fatigued red-haired woman in the sterile bed next to him. The square of obsidian at the base of his neck glinting ever so often against his gray-tinted skin.

The bundle tried to wail louder... But what was this?

A mischievous cerulean eye blinked down at the bundle, a playful grin following as a younger man moved next to the crib that held the whimpering form. "Wow..." The young man pushed aside his long blonde bangs, revealing the orb of yellow citrine that was embedded in place of his left eye. "You're an ugly little thing, aren't you? I can't believe we lost Minato... But now we have _you_." He blinked and his eye and the citrine orb switched places, the bundle in the crib beginning to wail again as the young man moved away to sit down, a brief flush appearing over his golden skin before it faded.

Why was this happening? The space was too negative, too cold! All the bundle wanted to do was to get out of here! But no one was coming to help him. He didn't want to suffer. He didn't come into this world to suffer.

So

Why?

The light that was giving a brief respite to the bundle was blocked off. The bundle looked up, whimpering again at the massive form looming over him.

Broad shoulders, a muscular stature, with purple hair falling down his back and cheeks in wild spikes, some of it tied in a pony-tail. Though it was superfluous.

The newcomer's face was imposing as well: a square jaw, a passive expression, and the eyes...

One was a piercing black while the other was a swirling red.

This man, with his purple skin-tone and an orb that was half blue tanzanite and half cinnabar embedded in his chest, looked down into the crib for a long while.

Observing. Taking in the site of the foreign pile of flesh.

Finally, he reached into the crib. He took the squirming bundle in his large but delicate hands and cradled him close to his chest. He carried the bundle out of the charged room and stepped onto the balcony: the cool evening air almost drowning out the city noise below.

Almost.

The man sat down in the nearest chair he could find, holding the bundle (who had calmed down by a longshot) and gently rocking him.

This was... better, the bundle realized. This was warm, this was... nice. Positive. This was what he wanted; what he needed.

"Hello. Minato - Sardius." The large man said, the bundle looking up at him. The man looked down, a lop-sided grin on his face. "No. That is incorrect. You are no longer Minato. You are his son."

The man held the whining form of a newborn babe: his blonde hair still wet from the nurse's wash and his cheeks soft and pudgy. The baby looked up at him with those sparkling blue eyes but the most stunning feature had to have been the star-shaped piece of sardius in his right hand.

"He promised me," The purple man went on, "That everything would be alright for me... For all of us. If I just believed in him. I guess that... that I have to believe in _you_ now. Alright then." He nodded, "Naruto – Sardius... I believe in you. I know you won't disappoint me or any other Crystal who comes to you for leadership. And I will do my best to help protect you and everyone you hold dear."

* * *

 **A/N:**

 **1\. First of all, the names. It wouldn't really make sense to replace canon characters' names with gems (for those who it applies to) so I made it part of the names that they would refer to each other with in either formal times, angry times, or initial introductions.**

 **2\. Samehada's description should give some hinting as to one of the pairings in this fic.**

 **And... that's all I have for now. I really don't know if I'll keep up with this one, since fanfiction has somewhat lost its spice for me in favor of original work and commissions, so... Yeah. Review if you'd like.**

 **\- Tyranno's girl.**


	2. The Vortex and the Seal

Konoha City was a busy metropolis: cars filling the streets in the purgatory that was rush-hour traffic, food trucks peddling gastronomical comforts while looking out for health inspectors or foodie reviewers.

There was a small layering of smog but, thanks to the environmental efforts of the city council led by Mayor Tsunade, they were keeping it at bay.

11th Street High School had just let out for the day, teens texting their parents and nannies for their rides, others making out where they shouldn't be, some even discussing deals of... unsavory natures.

Messy spikes of blonde peeked above some heads but were obscured by taller ones. Eventually, 16 year-old Naruto Uzumaki managed to get out of the crowded school. His stomach was growling like a cornered dog and he wanted nothing more than to get home to either make something to eat or get some money for food.

"Bye Naruto!" The occaisional person called out, Naruto waving back to them: the piece of Sardius in his hand glinting in the sun.

He walked down the streets, gripping the straps of his backpack tighter when he got to a more urban area.

"Hey Blondie Locks..."

Naruto groaned, looking to his left when he saw the visage of the local tattoo parlor smirking at him. "What is it Sai? I don't think I should be talking to someone who the truant officers are after so often." Sai rolled his eyes,

"As if. You know damn well a few years ago you were ditching school to either hang with me or those freaks of yours." Naruto's eyes narrowed, the gem in his hand sparking,

"Samehada, Fugaku, and Deidara aren't _freaks_! They're Crystalline Spirits. It's completely different!"

Sai shrugged him off, "So, you wanna get another tattoo? I'll treat ya, Blondie Locks."

Naruto shook his head, his shoulders relaxing when he realized Sai was just going through his usual 'stop ignoring me' teasing. "Nah. Mom and Fugaku flipped their shit when they saw the one on my stomach. Though I may hit you up for a piercing."

"Hey," Sai waved Naruto off when he started walking again, "I'm always here. _Some of us_ don't waste our time in school. Bye Blondie."

* * *

Naruto lived on the top floor of the Fox Kettle Apartment complex. It was a long elevator ride, and an even longer stair trip, but he loved it all the same. It allowed for some privacy, as well as some of the best views in the city.

Oh, when the sun rose and Naruto woke up early enough to catch it... It was _stunning_.

He opened the door, tossing his backpack onto the floor and removing his sweater, the spiraling tattoo he had gotten on his stomach briefly showing before he smoothed his shirt down. "Hello?" He called out, walking through the apartment, "Anybody home?"

"'Is any _one_ home'..." A tired old voice corrected between sips of tea in the main room, "Would be the correct order."

"Hey Fugaku - Obsidian." Naruto walked over and hopped onto the easy chair across from where the man was sipping tea, "How's your day been?"

Fugaku slowly opened his eyes, looking at how Naruto had grown since... _That day_.

" _Don't you tell me to calm down! Look at where we are now!"_

"This day has been... fine. Mina-" He cleared his throat, "Naruto, do you have any of that 'homework' that needs completing?"

Naruto shook his head, "All I have to do is study for English tomorrow. But I was hoping to get something to eat first..."

Fugaku set his empty tea cup down, the obsidian piece vanishing before a wallet appeared. "Here." Fugaku gave Naruto a few twenty-dollar bills. "Go see if Samehada or Deidara will take you."

"Yes! Thanks Fugaku!" Naruto's first instinct was to jump over and hug the man, but he knew from years living with him that he would recoil from him at every attempt.

Instead, Naruto walked up the stairs that led to the roof. On his way he passed the door that led to Samehada's room. It was locked. There was a firm rule about never bothering the giant man when the room was locked, even if it sounded like there were _two_ people in there instead of _one_.

Naruto opened the door to the roof and found one of the two people he was looking for. Deidara – Citrine was aiming a giant shimmering citrine cannon towards the sky. He smirked, the orb of citrine in shining from under his bangs as he fired: several golden birds soaring up and exploding after a while.

"Let's kick it up a notch!" Deidara cocked the cannon to make sure it was loaded with enough energy before firing again, larger birds flying farther before exploding into multicolored clouds. He laughed at the brilliant spectacle, letting the cannon vanish as he heard Naruto approaching from behind. "Beautiful, huh? The most breath-taking art you could ever hope to see on this planet!"

"Mm-hm." Naruto nodded, "They really are pretty. Hey, so Fugaku gave me money. Let's go eat!" Deidara grinned at that. Despite none of the Crystalline Spirits _needing_ to eat, he did like the sensations that human food gave him.

"Hey, as long as Fugi's paying, I'm down!" He snapped his fingers, a new form appearing behind him. Though still made of citrine, it was a large bird. It flapped its wings once before bending over so Deidara and Naruto could get on.

"Alright, let's get going!" Naruto whooped, Deidara kicking the bird's side so it would take off in the direction of the local Asian fusion restaurant.

* * *

"Oi~!" Naruto called out with a wave when Deidara and him walked into the small establishment. They sat down at the streetside bar, the young blonde adding, "Ichiraku! Come on, I've got money!"

"Yeah, yeah..." The old owner of the restaurant walked over, his daughter at his side, "What'll ya have?"

Naruto thought for a moment before nodding, "We'll take two Naruto Specials, please!" Ichiraku frowned,

"You know, you _could_ just tell me what kind of ramen you'd like instead of-"

"Give him the Naruto Special, Ichiraku!" Deidara insisted, knocking his fist against the table, "Come on, give him the Special, hun!" Ichiraku eventually just shook his head and went to work making two bowls of miso ramen with the left over fish cake from the earlier rush.

Naruto paid the man and after giving Deidara a proper fist-bump for bringing him here, they both began to eat. "Fuck, I needed this..." Naruto said between mouthfuls. He wasn't sure if it was his biology or his age but he could really pack it away; the lunches at school simply weren't enough.

Naruto was halfway through his bowl when he looked behind himself, moreso towards the sky. "Hey..." He took his phone out of his pocket and looked at the time, "It shouldn't be sunset yet..."

"Hm?" Deidara swallowed his mouthful and looked where Naruto was. If he had a stomach, it would have sunk. "We need to go." The citrine bird reappeared, Deidara forced Naruto onto it before hopping on himself. "Now!"

"Deidara, wait!" Naruto did his best to rearrange himself before Deidara took off, "Deidara!" Though, as they were flying, Naruto was able to get a better look at things: people panicking down below... And the sky growing black, starting from the swirling vortex that was growing bigger and bigger up above.

* * *

"Damn it..." Fugaku seethed as he looked at the expanding vortex through an obsidian telescope, "A Warp Star? _Here_? Why?!"

The two of them had rushed to the city pier to get a clear view of the vortex, chaos starting to build all around them.

Samehada shook his head, "Something's trying to come through. But if that rift gets any bigger, it could tear the ozone around this planet apart." And that wasn't even bringing up the fact of what could _possibly_ be trying to gain access to Earth in such a way.

"Samehada – Agate! Fugaku – Obsidian!" The two looked up just as Deidara landed with Naruto in tow, the teen trembling from the far drop. "What's going on, huns? The skies are going pitch-black and _completely_ ruining the aesthetic of this planet!"

Fugaku let the telescope disappear, glaring at Deidara. "Well, look who decided to join us at last. You _do_ realize that protecting this planet takes priorities over your little day-trips, right?!" Deidara flinched back before snapping,

"Well, if it were up to you, Naruto would starve! Of course I was going to take him out for food!" Naruto made his shaky way over to Samehada, the large man looking up at the vortex in the sky; ignoring the two squabbling men across from him.

"Is everything going to be alright?" Naruto asked him. Of course it would be, the Crystalline Spirits were here to protect the planet from anything that might try to harm it or the people on it.

Everything would be fine... Even with Fugaku and Deidara screaming at each other.

Fugaku grit his teeth, refusing to pull at his hair though the temptation was great, "This _never_ would have happened if Minato were still here!"

"Oh, _here we go_!" Deidara scoffed, "Look, I'm not about hearing this today, hun!" He snapped his fingers, the citrine cannon from before reappearing, "I'll just blast it until it goes away. Bon voyage~!" He fired off several rounds, all of the explosive birds being sucked into the vortex. "Damn it! Samehada, _you_ try something!"

Samehada stepped forward, holding up one of his hands to create a large scepter covered in shards of tanzanite and cinnabar with an orb composed of both materials on top. He aimed it at the vortex, a pillar of blue fire shooting towards the offending marker... Just to have the flames swallowed up.

"Damn it." Samehada hissed, stopping the flames in favor of trying to see if a torrent of scalding hot water would quell the swirling storm.

Naruto bit his lower lip, thinking about what he could do. He looked at the gem in his hand, wishing that he had his father's leadership skills or his power.

Wait a moment.

"Fugaku!" He shouted, the vortex above them beginning to roar and crackle, "What would my dad have done if he were here?!"

Fugaku shoved Deidara away, the blonde having climbed on top of him to pester him. "Minato would have created some sort of seal to defend us! I don't see why you needed to- Naruto!"

The blonde teen was already running down the pier. He knew where he needed to go.

* * *

Not too many blocks away was a local diner. The owner of it one Kushina Uzumaki was busy wiping down the counters, headphones in her ears, when she felt the door slam inward. The cause, of course, was her rowdy son.

"Mom, Mom!" Naruto shouted, his foot still extended from kicking in the door, "Holy _fuck_!"

Kushina removed her headphones, setting them on the counter and walking over to her son. "Now Naruto..." She said, calmly to reflect how she rested her hands on his shoulders. A moment later, she grabbed him in a headlock. "What the hell have I said about kicking in the door here, you little brat?"

"Mom~!" Naruto shouted, trying to escape, "Come on, this is important!"

Kushina wasn't hearing it, folding her arms and watching her son rave about something going on with the Crystalline Spirits. After a moment, she waved her hand, "Naruto, you know the Spirits have repeatedly told me not to get involved in their activities."

"But Konoha City's in trouble!" Naruto finally shouted, "Come on Mom, Fugaku said something about Dad having a seal and-"

As soon as Naruto mentioned his father, she set everything down and grabbed him by the wrist: dragging him along to the basement beneath the diner.

"If it's something of your father's," She announced, pulling on the dangling chain, a dusty light flickering on and revealing the wide expanse of odds and ends transpiring different time-periods and some that seemed foreign to Earth altogether, "It'll be in here."

Naruto stepped forward, looking around to see if anything would jump out at him. Yeah, Fugaku had mentioned a seal but Naruto had no idea what it would look like.

"So, what are we looking for, champ?" Kushina asked, moving some things out of the way so she could help. But Naruto still didn't know what he needed. He just knew that he needed to find it quick, things were really going to shit outside.

Wait a moment.

He jogged over to what appeared to be a golden chest with a stone of sardius on top.

"Naruto?" Kushina called as she walked over. She found Naruto holding the chest up with a smile on his lips.

"Found it!"

* * *

Kushina whistled as she drove Naruto and the chest to the pier. "Wow, things are... pretty bad, huh?" Naruto nodded, Kushina adding, "But lucky for us, your Dad's 'seal of approval' is going to make things right, huh?"

"Yeah!" Naruto whooped, Kushina parking so she could help Naruto bring the chest to where Deidara had started firing into the vortex again; much to Fugaku's annoyance... Which wasn't much compared to the groan he let out when he saw Kushina accompanying Naruto.

"What are _you_ doing here, woman?"

"She helped me find it!" Naruto explained, pointing to the chest, "Dad's seal! It's going to help blow that vortex-thing to kingdom-come!"

Deidara was about to whoop Naruto's praises, but Fugaku shook his head, "He left it with _you_?!"

"Yeah, you guys should have just come over to the diner if you needed this so much." Kushina puffed herself up with a smile, opening up the chest to reveal...

Nothing.

"What?!" She let the chest fall to the ground, desperately searching the empty container, "No, no! It was here, I _know_ it was!"

"Damn you!" Fugaku seethed, "Do you see? _This_ is why we never involve you with anything! All you do is ruin-"

Kushina shot back up, storming over to Fugaku and jabbing a finger into his chest, "Fuck off, buddy! You can keep that 'ruin everything' schtick to yourself as well, I am _not_ taking it! All I'm trying to do is help! All I _ever_ try to do is help!" She grit her teeth, eyes growing wet with her growing frustration, "You three don't even let me see my son anymore..!"

"Mom..." Naruto tried reaching out for her, his heart breaking at the sight of her so distressed. The boards of the pier cracked and splintered around them, the floor beneath Kushina breaking apart. Before she could scream, Naruto jumped towards her and pulled her to safety. "Mom, are you okay?"

She had to regain her bearings, but she slowly nodded; catching her breath and standing up. After making sure she was alright, Naruto turned to Fugaku, "What did this seal-thing look like anyway?" Fugaku rubbed at his temples, the noise and quaking becoming worse.

"It was Minato's unique, _sacred_ seal. A beautiful spiral of several different intricacies deep in its swirls and-"

Naruto felt like he had been struck by lightning once Fugaku described what they needed. "I have the seal!"

"What?!" Fugaku, Samehada, and Kushina shouted, Samehada stepping forward and kneeling down so he was at Naruto's height.

"Naruto – Sardius... Please, if you have the seal, now would be the perfect time to produce it." Naruto smiled and nodded once before pulling up his shirt and revealing the spiral tattoo on his stomach. When he had been searching around his father's old things, he saw the scroll that had the seal on it... And took it to Sai so he could get a tattoo of it.

 _Something_ about it had spoken to him.

But for now, his little rebellious streak was proving to be a blessing in disguise. "Fugaku – Obsidian!" Samehada called out, Fugaku nodding and holding out his hands: two plumes of black fire flaring up. Deidara walked over, ruffling Naruto's hair as the other two got everything ready.

Kushina jumped out of the way as a powerful pulse of water ran over the remaining wood beneath them, Samehada etching out a replica of Naruto's tattoo beneath the group. When it was done, Fugaku shouted,

"Mina- Naruto! You have to get in the middle of the seal! This won't work otherwise!"

"What?!" Kushina shrieked, "You're shitting me! I'm not going to just stand here and watch you set my son on fire!"

Fugaku promptly shouted, "Damn you, woman! The seal needs to recognize Minato's gem and Naruto is the only carrier we have right now!"

"I don't care about that!" Kushina moved to block Naruto from stepping further, "We'll think of something else! We-"

"Mom." Naruto slowly walked around her, insisting, "Look, it's going to be okay. Trust me." With that, he jogged over to the etching that Samehada made, standing in the middle; the gem in his hand shining ever brighter.

"Right." Fugaku nodded, sending the flames forward to engulf the seal and the one inside.

He could hear his mother screaming, he could feel the subconscious wince that Deidara gave... But he didn't feel any pain. No, all he felt was warmth.

Warmth that, when he opened his eyes, he helped push upwards towards the sky. He held out the hand that held his gem and, though he hadn't the slightest idea of what he was doing, it glimmered as Fugaku's flames were overpowered and transformed into a brilliant vermillion color.

He grit his teeth, shouting at the vortex, "Hey ugly! This is _my_ city and _my_ planet! Don't you think you're tough shit, you're not entitled to _anything_!" The last word was said in a growl, the flames shifting form until they appeared as a great fox.

The fiery beast hissed, bounding up to the vortex. It abruptly burst into a flare that held the intensity of an exploding star. Everyone had to shield their eyes so they wouldn't be blinded. The vortex howled as its form was burned away: first from the edges and then from the inside out.

It gave another piercing cry of death as its form vanished, ashes flying towards the endless expanse of space. And then...

All was still.

* * *

"Aw, man..." Naruto groaned around a mouthful of hamburger, "I burned off all the ramen I ate at Ichiraku's..."

"So, what?" Kushina sat down next to her son, wrapping her arm around his neck, "Are you saying my cooking isn't good enough for you, you little brat?"

Kushina's diner was still empty due to all the chaos earlier, so the group was inside to wait things out before Kushina could drive them home.

Deidara was sucking away at a lemon popsicle (not so much for the flavor as much as him liking how it painted his mouth) and Samehada slowly eating a plate of dango dumplings. The fact that the large spirit had such a sweet tooth was always an interesting element.

Fugaku, on the other hand, sat at the far end of the restaurant: a cup of tea, brewed on his own, resting in front of him.

"You did..." Samehada began, "A good job today, Naruto."

Naruto beamed, a flush growing on his cheeks, " _Really_?" Deidara wholeheartedly agreed,

"Yeah, hun! The way you swooced right in and saved the day with your tattoo was the piece de artistic resistance!"

Naruto took another bite of his burger, glancing over at Fugaku. He wished the other spirit would join them. However, he had other things to worry about.

"Although..." Kushina pinched Naruto's ear, "We're going to have to talk about you hanging out with that tattoo artist."

"Mom~!"

* * *

…

…

…

"The transmissions from Warp Star Alpha-Delta have ceased."

"Oh. Oh _really_? Tell me again what that meansss, boy."

…

… _Beep. Whhhiir! Click-Beep-Click_.

"Warp Star Alpha-Delta has, in fact, been destroyed. And the only beings strong enough to have destroyed it are-"

"Crystal Sspiritss! Oh, they've been ssso kind as to extend an invitation! We shouldn't keep them waiting..."

"Yes sir." There was a flash of blue electricity in the darkness. Then a loud roaring whir. Then...

Nothing.

* * *

 **A/N: Well, that wasn't too bad for being something used to vent. Let's see if I can get motivated to continue this whole 'SU-AU' thing any further.**

 **Also, unlike _'Of Youkai'_ and _'Goldstar Barrier'_ I may follow some episodes but I want to expand a bit on this AU. So, yeah... Review if you feel like it, thanks for reading!**

 **-Tyranno's girl.**


End file.
